Caterpillar D7
The Caterpillar D7 is a large track-type tractor designed and manufactured by Caterpillar Inc. Though it comes in many configurations it is most commonly sold as a bulldozer equipped with a detachable large blade and a rear ripper attachment in recent years. Early versions had Bulldozer gear by 3rd party manufacturers like LeTourneau added that used cable control units before hydraulics became more common after WWII. A lot of tractors were sold for pulling Scrapper boxes and trailed implements. The UK received some of the early models under lend lease during WWII. After the war they were sold off and contractors and farmers bought them. A few examples have started to be saved and are appearing in plant collections and at shows. History 2010 (blade removed for transport)]] *1935: Caterpillar RD7 5E series introduced, as upgrade to the Caterpillar Diesel Fifty *1935; Caterpillar RD7 9G series replaces the 5E series. *1938: The "R" prefix dropped, D7 débuts. *1940: D7 7M series starts production *1944: D7 3T series introduced; Deal with LeTourneau ends, and Cat introduces own Bulldozer Blade design. *1955: D7 3T Series ends production with over 28,000 machines produced; D7C 17A series introduced with new D339 diesel engine. *1959: D7C ends, 140 hp D7D introduced. (Both retain 17A series reference) *1961: D7D replaced by D7E 48A series. Horse power increased to *1969: D7E replaced by D7F of . *1975: D7F replaced by D7G of . *1986: D7G replaced by D7H with elevated sprocket design. The D7H was the first D7 with the elevated drive sprocket undercarriage *1996: D7H replaced by D7R Current D7 Models Blades Several types of bulldozer blade can be used on the front of the tractor: * A straight blade ("S-Blade"): A short blade and has no lateral curve, no side wings, and can be used for fine grading * An angle blade: Is held by an U shape frame that has 3 holes on each side, to set the blade to 3 positions: to the right, center, and left. * A universal blade ("U-Blade"): A tall and very curved blade, and has large side wings to carry more material * An "S-U" combination blade: A shorter blade, with less curvature, and smaller side wings Various other blade types are used including landfill U-Blades, woodchip U-blades, and two-way blades for work inside the holds of ships. Rippers Several versions available; * Single shank for rock * Multiple shank for general surface loosening UK Preserved Examples * D7 (7M) SN 9103 has been preserved by ACMOC member Paul Tolfield. This machine has a Caterpillar D8800 engine of 80 hp. The machine has a 5F - 4R gearbox with FR shuttle transmission.CP&M Vol 1 no. 10, June 2003 * Another D7 is in the Fred Knight collection * The Vintage Excavator Trust site in Cumbria has a D7 with Wide tracks stored there. (the machine looks in a very poor state of repair and the wide tracks are self made) * There may be one in the S.E. Davis & Son Ltd. collection. (A they have every other one from a D2 to a D9 ) * D7 3T (4T) from 1944 in the collection of John Walker collection from Retford in Nottinghamshire. (Photo above) * D7E (47A) sn 1624 from 1963 of C. Pitchfork of Kinoulton ? seen at the Rempstone Steam Rally 2010 See also *List of Caterpillar Models *Caterpillar Engines *LeTourneau *Caterpillar D8 *Caterpillar D6 *Komatsu *List of Collections *Construction Plant Dealers References *Giant Earthmovers "An Illustrated History", by Keith Haddock, Published by MBI, ISBN 0-7603-0369-X External links * Caterpillar D-Series Track-Type Tractors - Official Caterpillar website D7 Category:Bulldozers Category:Caterpillar D7 Category:Tractors by model number Category:Tractors built in the United States Category:Tractors of unknown horsepower Category:7 (model number)